1. Field of the Invention
The present invention relates to wireless communication, and more specifically, to a method and apparatus for transmitting and receiving data.
2. Related Art
Long term evolution (LTE) is a key next generation mobile communication standard based on 3rd Generation Partnership Project (3GPP) Technical Specification (TS) Release 8.
As described in 3GPP TS 36.211 V8.7.0 (2009-05) “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 8)”, LTE physical channels may be divided into downlink channels (Physical Downlink Shared Channel (PDSCH) and Physical Downlink Control Channel (PDCCH)) and, uplink channels (Physical Uplink Shared Channel (PUSCH) and Physical Uplink Control Channel (PUCCH)).
PUCCH is an uplink control channel for use in transmitting uplink control information such as a hybrid automatic repeat request (HARQ) ACK/NACK signal, a Channel Quality Indicator (CQI), and a scheduling request (SR).
Meanwhile, 3GPP LTE-A (advanced) as advanced 3GPP LTE is being adopted. There is a multiple input multiple output (MIMO) technology supporting at least 4 antenna ports and carrier aggregation and being introduced in 3GPP LTE-A.
In carrier aggregation, multiple component carriers are used. Component carriers are defined by center frequency and bandwidth. A downlink component carrier or a pair of an uplink component carrier and a downlink component carrier corresponds to one cell. A User Equipment (UE), which is provided with services using multiple downlink component carriers, may be considered as being served by a plurality of serving cells.
In a Time Division Duplex (TDD) system, the frequency of a downlink is the same as that of an uplink. Accordingly, an uplink subframe is associated with one or more downlink subframes. ‘Association’ means that transmission/reception at the downlink subframe is associated with transmission/reception at the uplink subframe. For example, when a transmission block is received at multiple downlink subframes, a UE sends HARQ ACK/NACK for the transmission block at the uplink subframe associated with the plurality of downlink subframes.